Characteristics of Living Organisms NEET Notes | EduRev

Biology Class 11

NEET : Characteristics of Living Organisms NEET Notes | EduRev

The document Characteristics of Living Organisms NEET Notes | EduRev is a part of the NEET Course Biology Class 11.
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What is Living?

Living is something that is alive, something that can grow, move, reproduce, respire, and carry out various cellular activities.

  • Living things are made up of cells and are capable of carrying out various cellular activities. 
  • Birds, insects, animals, trees, human beings, are a few examples of living things as they have the same characteristic features, like eating, breathing, reproduction, growth, and development, etc. 
  • The different characteristics that best describe what a living thing is, are mentioned below:

Characteristics of Living Organisms

1. Growth

Growth is the ability of an organism to increase in size through Cell Growth and Cell Division.

  • Living organisms grow in mass and number. 
  • A multi-cellular organism increases its mass by cell division. 
  • In plants, growth continues throughout life in their meristematic area, but growth occurs to a certain age in animals.

Characteristics of Living Organisms NEET Notes | EduRevGrowth of a Plant

  • Unicellular organisms reproduce by cell division. 
  • Living organisms show internal growth due to the addition of materials and the formation of cells inside the body. 
  • The non-living organisms like mountains, boulders, crystals also grow but due to the addition of similar materials to their outer surface.

2. Reproduction

Reproduction is the process by which an organism produces an individual like its own. 
  • It is the formation of new individuals of a similar kind. Reproduction is not essential for the survival of individuals. It is required for the perpetuation of the population.
  • In sexual reproduction, two parents are involved in producing more or less similar kinds of individuals. 
  • In asexual reproduction single parent is involved, and the individual is a copy of the parent. Asexual reproduction may occur by fission, regeneration, vegetative propagation etc. Characteristics of Living Organisms NEET Notes | EduRev
  • In the unicellular organism, growth and reproduction are synonyms. Many organisms like mules, sterile worker bees, and infertile human couples do not reproduce.
  • Therefore, reproduction is not an all-inclusive characteristic of the living organism. However, no non-living object has the power to reproduce or replicate.

Try yourself:Reproduction is synonymous with growth in
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3. Metabolism

Metabolism refers to a series of chemical reactions that occur in a living organism to sustain life.

  • It is the sum total of all types of chemical reactions occurring in an individual due to specific interactions among different types of molecules in the interior of cells is called metabolism.
  • Metabolism is the internal process by which our body expends energy and burns calories. 
  • All activities of an organism, including growth, movements, development, reproduction etc. are due to metabolism.

Try yourself:Mark the incorrect statement w.r.t. metabolism.
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4. Consciousness

It is a property by the virtue of which an organism responds to an external stimulus or change in environment.  
  • It is the awareness of the surroundings and responding to external stimuli. External stimuli may be physical, chemical or biological. Plants also respond to stimuli like light, water, gravitation, pollution etc. 
  • All living organisms prokaryotic to eukaryotic respond to different kinds of stimuli.
  • A human being is the only organism who is aware of himself. 
  • Consciousness, therefore, becomes the defining property of living organisms.

What is Biodiversity?

“Biodiversity is the variation among living organisms from different sources including terrestrial, marine and desert ecosystems, and the ecological complexes of which they are a part.”

  • Biodiversity describes the richness and variety of life on earth. 
  • It is the most complex and important feature of our planet. Without biodiversity, life would not sustain.
  • The term biodiversity was coined in 1985. It is important in natural as well as artificial ecosystems. 
  • It deals with nature’s variety, the biosphere. It refers to variabilities among plants, animals and microorganism species.
  • Biodiversity includes the number of different organisms and their relative frequencies in an ecosystem. 
  • It also reflects the organization of organisms at different levels.
  • Biodiversity holds ecological and economic significance. It provides us with nourishment, housing, fuel, clothing and several other resources. 
  • It also extracts monetary benefits through tourism. Therefore, it is very important to have a good knowledge of biodiversity for a sustainable livelihood.

Types of Biodiversity

There are the following three different types of biodiversity:

  1. Species Biodiversity
  2. Ecological Biodiversity
  3. Genetic Biodiversity

Characteristics of Living Organisms NEET Notes | EduRev

1. Species diversity 

  • Species diversity refers to the variety of different types of species found in a particular area. 
  • It is biodiversity at the most basic level. It includes all the species ranging from plants to different microorganisms. 
  • No two individuals of the same species are exactly similar. For example, humans show a lot of diversity among themselves.

2. Ecological diversity 

  • An ecosystem is a collection of living and non-living organisms and their interaction with each other. 
  • Ecological biodiversity refers to the variations in the plant and animal species living together and connected by food chains and food webs. 
  • It is the diversity observed among the different ecosystems in a region. 
  • Diversity in different ecosystems like deserts, rainforests, mangroves, etc., include ecological diversity.

3. Genetic diversity 

  • It refers to the variations among the genetic resources of the organisms. 
  • Every individual of a particular species differs from each other in their genetic constitution. 
  • That is why every human looks different from each other. 
  • Similarly, there are different varieties in the same species of rice, wheat, maize, barley, etc.

Try yourself:Which one of the following has maximum genetic diversity in India?
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Importance of Biodiversity 

Characteristics of Living Organisms NEET Notes | EduRev

Biodiversity and its maintenance are very important for sustaining life on earth. 

A few of the reasons explaining the importance of biodiversity are:

1. Ecological Stability 

  • Every species has a specific role in an ecosystem. 
  • They capture and store energy and also produce and decompose organic matter. 
  • The ecosystem supports the services without which humans cannot survive. 
  • A diverse ecosystem is more productive and can withstand environmental stress.

2. Economic Importance 

  • Biodiversity is a reservoir of resources for the manufacture of food, cosmetic products and pharmaceuticals. 
  • Crops livestock, fishery, and forests are a rich source of food. 
  • Wild plants such as Cinchona and Foxglove plant are used for medicinal purposes. 
  • Wood, fibres, perfumes, lubricants, rubber, resins, poison and cork are all derived from different plant species. 
  • The national parks and sanctuaries are a source of tourism. They are a source of beauty and joy for many people.

3. Ethical Importance 

  • All the species have a right to exist. 
  • Humans should not cause their voluntary extinction. 
  • Biodiversity preserves different cultures and spiritual heritage. 

Biodiversity in India 

  • India is one of the most diverse nations in the world. It ranks ninth in terms of plant species richness. 

Characteristics of Living Organisms NEET Notes | EduRevBiodiversity Hotspots in India

  • Two of the world’s 25 biodiversity hotspots are found in India. It is the origin of important crop species such as pigeon pea, eggplant, cucumber, cotton and sesame.
  • India is also a centre of various domesticated species such as millets, cereals, legumes, vegetables, medicinal and aromatic crops, etc. India is equally diverse in its faunal wealth. 
  • There are about 91000 animal species found here.
  • However, diversity is depleting at a drastic rate and various programmes on biodiversity conservation are being launched to conserve nature.
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